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Seizure triggers for people with photosensitive epilepsy

There are a number of things that could trigger a photosensitive seizure. Because people’s sensitivities are so individual, not everything will affect every person with photosensitive epilepsy. The following are some of the things that people ask us about:

Bicycle lights (red and white)

UK law says that these lights mustn’t flash at less than one or more than 4 flashes a second. Provided the lights comply with the law, they are unlikely to cause a problem.

Ceiling fans

Some ceiling fans can rotate at a fast speed. Looking at light through them could be a seizure trigger.

Christmas lights that flash

There is no UK law that covers the flash frequency of Christmas lights. It’s therefore possible that they could trigger a seizure.

Computer screens

Computer screens are unlikely to be a seizure trigger. However if there are flashing or flickering images, or some types of pattern on the screen, these could be a seizure trigger.

Flashing novelty badges

These can flash at any rate. It is therefore possible that they could be a seizure trigger.

Interactive whiteboards

Unless what is shown on an interactive whiteboard flashes or flickers, or has some types of pattern, they are unlikely to be a seizure trigger.

Light bulbs (any type)

These are only a possible seizure trigger if they are faulty. Otherwise, they shouldn’t cause a problem.


These are some examples of patterns that could be seizure triggers:

  • High contrast patterns such as black and white stripes
  • Striped or patterned materials and walls
  • Patterns in some television programmes, video or electronic games
  • A moving escalator

Strobe lights

We have been unable to find any current official guidance on the recommended flash rate of strobe lights. It is therefore possible that they could be a seizure trigger.


These may trigger a seizure if the tubes flicker. Otherwise, they shouldn't cause a problem.


Looking directly at certain patterns caused by sunlight could be a seizure trigger for some people. Examples of these situations are:

  • Sunlight through slatted blinds
  • Sunlight through trees, viewed from a moving vehicle
  • Sunlight reflected off moving water or off snow
  • Sunlight through moving leaves
  • Sunlight through railings, as you move past them

TV screens

Modern TV screens don’t flicker so are unlikely to be a seizure trigger for most people. However, if a programme shows images that flash or flicker, these could be a seizure trigger for some people.

Wind turbines

Large wind turbines rotate at a rate that is unlikely to trigger a seizure. Smaller turbines can rotate at a faster rate. When these smaller turbines create a shadow and/or flicker effect with the sun, they could be a seizure trigger.

Useful information

If you are concerned about flashing artificial lights, you can complain to your local council. They should consider complaints about ‘nuisance lights’, but they may not take account of someone’s photosensitive epilepsy. This is because they only have to consider how the nuisance affects the ‘average person’, not people with ‘rare sensitivities.’

If you would like to see this information with references, visit the Advice and Information references section of our website or contact our Epilepsy Action freephone Helpline on 0808 800 5050.


This information has been produced under the terms of The Information Standard.

  • Updated June 2018
    To be reviewed June 2021

Comments: read the 9 comments or add yours


I was wondering if we can get filter glasses in the uk?
my younger sister (she is 15 but only the size of a 10 year old) is not having a good start to the this year she has been having more and more seizures every week and it seems to be traveling to and from school or when we travel as a family she is having to go to hospital as they started to last for up to 20 minutes that's the worse one so far it took 15 minutes after the buckle for her to stop and she didn't really come round for another hour after.
she use to just have very small ones and would be in and out within minutes
I worry for my mum and sister because what is out there to protect her at night when no one can see it happening ???
any advice would be great
thank you

Submitted by vicky on

Hi Vicky
I believe it is possible to get different coloured lenses in glasses. You’d need to talk to the optician about this.
In case your sister has photosensitive epilepsy, I am linking you to all our information about it. https://www.epilepsy.org.uk/info/photosensitive-epilepsy
Sometimes when no epilepsy medicines are working a person can ask for a full review of the condition with an epilepsy specialist. It is possible this is what your sister needs: https://www.epilepsy.org.uk/info/diagnosis/getting-right-treatment-care-...
Meanwhile, depending on the type of seizures she has, she may benefit from a bed alarm: https://www.epilepsy.org.uk/info/daily-living-aids#alarms
I do hope this information is helpful.
Epilepsy Action Helpline Team

Submitted by Cherry, Epileps... on

Thank you for publishing this article. We appreciate you spending time to put
this together.

Submitted by Andrews Carpet ... on

I was almost relieved to hear from a specialist that I was not imagining some types of light ( halogen headlights, for instance) can cause problems for me. I loved to go fishing but had to quit . Reflections on water bothered me terribly in the evening. Light through trees on shore were things that, along with the ripples and patterns on the water may have started something. Especially when meds needed adjustment I don’t want to risk being on the water with someone trying to get to shore.
I would like to see if anyone has suggestions for spending time outdoors. Maybe some ideas between us can help enjoying the sunlight and gorgeous moon be safer.

Submitted by Teri on

Is it possible that very bright sunlight, or rather high UV values as found in Texas where the UV index is often 3 x that in the UK can trigger focal seizures even though on medication and free for over 6 months.

Submitted by Richard Moseley on

Any relation between the older radars and photosensitive seizures??
I have in excess of 25,000 radar hours and was diagnosed at the age of 54 as an epileptic, twenty years ago. I still have epilepsy & have no doubt that radar RF & other aviation, civil & military equipment caused my epilepsy. Is there any on-going research into the link of epilepsy & radar?

Submitted by Bob on

Hi Bob

We aren’t aware of any research between epilepsy and radar.



Epilepsy Action Helpline Team

Submitted by rich on

Can vividly imagining the "flashing lights" you once saw before having a seizure trigger seizures? I imagine a lot of those and the image would linger in my mind as if I had just hallucinated and that causes a worry as to maybe would it catch me just by imagining or thinking about it. And also I read somewhere about photosensitive epilepsy that being tired can trigger seizures. What kind of tiredness do they mean? I want to know is it safe for a person with photosensitive epilepsy participate in sports, exercise or even jog every day?

Submitted by Phil on

Hello Phil

There’s no evidence that thinking about flashing lights triggers seizures. Tiredness can be a seizure trigger for many people with epilepsy, not just those with photosensitive epilepsy. Usually when people talk about tiredness triggering a seizure they mean the sort of tiredness they feel when they’ve not has as much sleep as usual, but it varies from person to person.

With the right support and safety precautions, most sport and leisure activities are safe for people with epilepsy. A very small number of people find that strenuous exercise increases their likelihood of having seizures. This shouldn’t mean they need to avoid exercise completely, but just to make sure they don’t push themselves too hard. You might find our sports and leisure page useful.


Epilepsy Action Helpline Team

Submitted by rich on

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